CYBERNET Solution Antenna analysis by Ansys HFSSAnsys HFSS enables the calculation of finite size...

CYBERNET Solution

This solution catalog indicates the example of the usages of CAE software provided by Cybernet Systems.

CYBERNET SYSTEMS MALAYSIA SDN. BHD. (1305642-T)

Antenna analysis by Ansys HFSS

Challenges in antenna design

In recent years, the demand for antennas grows dramatically, and not only high performance, but also multi-functionalization and miniaturization are required. As a result, the antenna structure becomes complex. Because there are multiple structural parameters, optimizing the antenna characteristics is a very difficult task. When designing an antenna, it is necessary to not only optimize the characteristics of the antenna itself, but also include the behavior of the electromagnetic field around the antenna. Therefore, it is necessary to visually understand the electrical characteristics including the area around the antenna. However, it takes a lot of time and cost to perform simple simulations and repeated prototype experiments. By using the high frequency electromagnetic field analysis tool - Ansys HFSS, you can solve these problems in antenna design.

Antenna analysis by Ansys HFSS

(1) With Ansys HFSS, you can easily create models such as helix and spiral. It also has a basic antenna model, which allows you to quickly model your antenna.

(2) By setting parameters to the structural value of the antenna, it is possible to easily grasp the characteristic changes due to the structural parameters, and it is possible to efficiently optimize the antenna characteristics.

Helix Spiral Horn Parabola

Printed inverted F antenna Smith chart when the distance d is changed

d: Short distance

a: Total length of meander line

Change in resonance frequency when the total length a is changed

CYBERNET SYSTEMS MALAYSIA SDN. BHD. (1305642-T / 201801043610)http://www.cybernet.asia/ [email protected] Tel: +603 2201 1221

The company names and product names described are generally trademarks or registered trademarks of each company.

(3) Sufficient output is available to evaluate antenna characteristics, including antenna gain, radiation pattern, and radiation efficiency.

(4) The adaptive auto-mesh function automatically generates an accurate mesh and realizes stable and highly accurate analysis even for complicated shapes.

(5) There are multiple analysis engines that are useful for antenna analysis. By selecting them appropriately, the memory used and analysis time can be greatly reduced.

• FEM Solver (finite element method)- A universal solver that can efficiently

analyze all shapes- Faithfully reproduce the electromagnetic

field phenomenon that actually occurs

• Integral Equation Solver (moment method)- Efficiently analyze models that are mainly composed

of conductors- Good at analyzing scattering characteristics

of antennas and electromagnetic fields

• Physical Optics Solver (PO)- Approximate analysis of high frequency

phenomena-Efficiently analyze structures that have electrically large and smooth curved surfaces

• Hybrid SolverA solver that combines the finite element method and the moment method. Large-scale analysis is possible with less memory

Smith chartReturn loss characteristics

Current distributionRadiation pattern

Radiated power

Power supply

Radiation efficiency

Initial mesh Final meshIntermediate mesh

Automatic generation of high-precision mesh



(6) By utilizing the distributed analysis environment, it is possible to perform very large-scale analysis, which was considered unrealistic until now.

Analysis examples

<Index>

• 24GHz car radar analysis example (Finite Array function)

• Miniaturized design of printed inverted F type antenna

• Antenna design including supply circuit

• Antenna design considering the housing

• Analysis of smartphone built-in antenna near human body

• Effect of car chassis and windshield on antenna

• International Space Station S-band antenna analysis example

Distributed processing of analysis to PCs on the network

CYBERNET Solution



24GHz car radar analysis example (Finite Array function)

Ansys HFSS enables the calculation of finite size phased array antennas including coupling between antenna elements and array edge effects.Previously, in order to simulate a large phased array antenna, an infinite array was assumed and the operation of the antenna was approximated. The Finite Array function of Ansys HFSS can analyze a full-size array model based on one analysis result at high speed and analyze a full model considering the influence of edges.

Overview

Analysis Example

Model example

The entire display Top view

Far-field antenna pattern calculated with the Finite Array function. The solid line in the graph indicates a finite array and the dotted line indicates an infinite array.

Recommended for such people⚫ High-speed analysis of large-scale array antenna that takes time to analyze⚫ Understanding the effect of the characteristics of the power supply circuit on the antenna



24GHz car radar analysis example

Analysis Type

• Electromagnetic field analysis• Circuit analysis

Required products

• Ansys HFSS

Example of single antenna Return loss

Example of array antenna analysis using the Finite Array function

Array antenna consisting of 4 x 8 32 elements

Radiation pattern

Number of vertical and horizontal elements can be set from a single antenna

Radiation pattern

EffectivityThe radiation characteristics of the antenna change depending on the supply conditions of the antenna. You can design an antenna with Ansys HFSS alone, but by linking with the circuit simulator attached to Ansys HFSS, you can design an antenna supply circuit and an antenna design that takes the supply conditions of the supply circuit into account.

CYBERNET Solution



Miniaturized design of printed inverted F type antenna

If the antenna is downsized, the input impedance will decrease and the antenna characteristics will deteriorate. In addition, the characteristics of the antenna change significantly due to the influence of surrounding structures. Therefore, it is very important to understand which parameter of the antenna should be adjusted to match the characteristics. In the example, the structural value of the antenna is defined as a parameter, and the change in the characteristics when each structural value is changed is clarified. Design becomes easier because you can see how the characteristics change when miniaturized, and where to adjust to improve the changed characteristics.

Analysis Model

(a) Change the height of the antenna(b) Change the distance between the power supply point and the short

(c) Change the total length of the antenna

Analysis Result

Changes in properties for each structural parameter

(b) Change in Smith chart when changing the distance between the supply point and the short

(c) Change the total length of the antenna

Recommended for such people⚫ When designing a built-in antenna, the space given to the antenna is small and it is unknown how

to downsize it.⚫ Grasping changes in properties when changing structural parameters⚫ Design a small antenna with good performance

It can be seen that as the height of the antenna decreases, the circle on the Smith chart increases and the input impedance decreases.

By adjusting the position of the reverse F short, the circle on the Smith chart can be made smaller and the input impedance can be stepped up.

Adjust the total length of the antenna to match the desired frequency.

(a) Change in Smith chart when the height of the antenna is changed

http://www.cybernet.co.jp/ansys/images/case/analysis/320/fig01.gif



http://www.cybernet.co.jp/ansys/images/case/analysis/320/fig04.jpg





Final characteristics of printed inverted-F antenna

(a) Smith chart (b) Return loss characteristics

(c) Radiation characteristics (d) Current distribution

Required Product

• Ansys HFSS

Analysis Type

• Electromagnetic field analysis

EffectivityIn an environment where a small built-in antenna is placed, there are many parts around it, which greatly affects antenna characteristics.If changes in characteristics due to structural parameters are understood, it is possible to facilitate miniaturization design and quickly improve characteristics that have been deteriorated due to the effects of the surroundings.




CYBERNET Solution



Antenna design including supply circuit

It is possible to analyze the radiation characteristics and gain of the antenna in consideration of the circuit characteristics by incorporating the supply circuit including the distributor and amplifier in the printed Yagi array antenna.

Analysis Model

Result

Printed Yagi array antenna and supply circuit

Input power in phase 180 degree phase inversion with amplifier

The power and phase obtained from the result of the circuit simulation are automatically set to supply the antenna.

Since the two amplifiers have the same gain and phase delay, the power supply conditions are also the same.

Since the two amplifiers have different gains and 180 degrees different phases, the power and phase are 180 degrees different.

Recommended for such people⚫ Power supply circuit design that can bring out the performance of the antenna⚫ Understanding the effect of the characteristics of the power supply circuit on the antenna









Analysis Type

• Electromagnetic field analysis• Circuit analysis

Required Product

• Ansys HFSS

Antenna Radiation Pattern Considering Excitation of Circuit Simulator

Input power in phase 180 degree phase inversion with amplifier

Antenna gain

Set the same gain and phase for antenna elementsAmplifier 1: Gain = 0, Phase delay = 0Amplifier 2: Gain = 0, Phase delay = 0

Set different gain and phase for antenna elementAmplifier 1: Gain = 2, Phase delay = 180Amplifier 2: Gain = 1.8, Phase delay = 0

EffectivityThe radiation characteristics of the antenna change depending on the supply conditions of the antenna. It is possible to design the antenna with Ansys HFSS alone, but by linking with the circuit simulator attached to Ansys HFSS, it is possible to design the antenna supply circuit and the antenna design considering the supply conditions by the supply circuit.





CYBERNET Solution



Antenna design considering the housing

When the antenna is installed in the housing, the characteristics will change significantly.Therefore, it is important to design the antenna in consideration of the change in the characteristics when it is installed in the housing. In the following example, the GPS ceramic patch antenna is analyzed including the housing to clarify the changes in the characteristics when the housing is installed.

Analysis Model

(a) Housing + antenna (b) Antenna only (without housing)

GPS ceramic patch antenna

Result

Characteristics of antenna alone and characteristics when assembled in case

(a) Return loss characteristics (b) Axial ratio characteristic

Housing

Recommended for such people⚫ When the antenna is incorporated in the housing, the characteristics change greatly⚫ Implemented antenna design considering changes in characteristics when incorporated in a

housing

reflector

Square patch

Ground board

ceramic

reflector

Antenna only

Antenna onlyWith housing

incorporated (no tuning)

With housing incorporated (no

tuning)

20MHz shifts to the lower frequency when

incorporated in the case

GP frequency 1.5742GHz







Antenna characteristics when assembled in case after tuning

(a) Return loss characteristics (b) Axial ratio characteristic

Radiation characteristics of GPS ceramic patch antenna

(a) Two-dimensional radiation pattern (b) Three-dimensional radiation pattern (c) Radiation efficiency

Required Product

• Ansys HFSS

Analysis Type


EffectivityIt is possible to confirm changes in the antenna characteristics when incorporated in the housing, and it is possible to feed back to the design of the antenna itself.

With housing incorporated (after tuning)

With housing incorporated (after tuning)

Individual characteristics of tuned antenna

Individual characteristics of tuned antenna

Tune the frequency of a single unit 20MHz higher to match the characteristics when assembled in a case





CYBERNET Solution



Analysis of smartphone built-in antenna near human body

In the usage environment of a smartphone, the influence of the human body on the antenna characteristics greatly affects the actual communication characteristics. Therefore, it is important to understand what the antenna characteristics will be like when approaching the human body. In the following example, the deformed inverted F antenna mounted on the smartphone near the human head is analyzed, and the input impedance characteristics, the radiation pattern, the radiation efficiency, the electric field distribution, and the SAR distribution in the human head near the human body are calculated.

Analysis Model

Human head and smartphone analysis model

Result


Change in input impedance

Recommended for such people⚫ Analyze the characteristics that the human body gives to the antenna characteristics⚫ Implemented antenna design considering changes in characteristics when approaching the human

body⚫ SAR (Specific Absorption Rate) analysis

Human head

Built-in antenna (deformed inverted F

antenna)

Smartphone

Smartphone only

Smartphone only

Near the human body

Near the human body






Three-dimensional radiation pattern Antenna efficiency

Electric field distribution SAR distribution

Required Product

• Ansys HFSS

Analysis Type


EffectivityIt is possible to confirm changes in the antenna characteristics when approaching the human body, and it is possible to provide feedback to the design.

Smartphone only

Near the human body





CYBERNET Solution



Effect of car chassis and windshield on antenna

The characteristics of the antenna change significantly due to the influence of surrounding structures. It is important to know in advance the changes in characteristics in the actual usage environment. In the example below, we analyze the GPS patch antenna installed in a car and clarify the effects of the chassis and glass.

Result

Comparison of antenna characteristics when assembled in a car (1)


Analytical model of car and GPS patch antenna

(c) Axial ratio characteristic

Recommended for such people⚫ Communication characteristics deteriorate

when an antenna is installed in a car⚫ Analyze the effect of car chassis and glass

on antenna characteristics⚫ Antenna design considering changes in

characteristics when incorporated in an automobile

In order to reduce the memory capacity,

analysis is performed using the HFSS-FEM

(finite element method) and HFSS-IE

hybrid solver.

[Memory used]FEM alone: 91G

↓When using hybrid

solver: 6G

Car model (IE-Solver)

Aluminum chassis

Automotive glass (4mm thickness)

GPS patch antenna (FEM-Solver)






Required Product

• Ansys HFSS

Comparison of antenna characteristics when assembled in a car (2)

(a) Radiation pattern in the longitudinal direction

of the vehicle

(b) Radiation pattern in the lateral direction of the vehicle

Characteristics of GPS patch antenna tuned to be optimal when installed in a car

(a) Smith chart (b) Return loss (c) Axial ratio characteristic

(d) 2D radiation pattern (vehicle longitudinal direction)

(e) 2D radiation pattern (vehicle lateral direction)

(f) 3D radiation pattern

EffectivityIt is possible to confirm changes in the antenna characteristics when incorporated in an automobile and feed it back to the design of the antenna itself.In this example, we confirmed the characteristics when it was installed in one place in the car, but the characteristics differ depending on the installation location. It is also possible to select the optimum position to install by electromagnetic field analysis.

Analysis Type


Embedded in car Embedded in carEmbedded in car(without glass) Embedded in car(without glass)Antenna only Antenna only









CYBERNET Solution




International Space Station S-band antenna analysis example

This is an analysis example of the S-band antenna installed on the International Space Station. Even if the analysis target is very large, 733λ, and it is usually difficult to analyze electromagnetic fields, it is possible to analyze with realistic PC specifications by using the Ansys HFSS Physical Optics solver. In this example, we were able to analyze with 47GB of physical memory.

Result

Current density distribution 3D radiation pattern from antenna

Analysis Type


Required Products

• Ansys HFSS• Ansys HFSS-IE Solver

Recommended for such people⚫ Antenna designers who are designing and experimenting with antenna characteristics, including

the target for antenna installation⚫ A designer who wants to carry out a large-scale antenna analysis design including an object of

100λ or more, which was difficult until now.

CYBERNET Solution Antenna analysis by Ansys HFSSAnsys HFSS enables the calculation of finite size...

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